# Physics 21-22

Flashcards by Mariapaula AR, updated more than 1 year ago
 Created by Mariapaula AR almost 6 years ago
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### Description

Basic physics knowledge

## Resource summary

 Question Answer Uniform Motion This describes an object that is travelling at a constant rate of motion in a straight line. This would be viewed as a straight line on a graph. Average Speed Uniformed motion that involves travelling a distance in a specified time. Example: 12m/s How can average speed be calculated from a graph? Average speed can be calculated from a graph using the rise and run and then following the formula for a distance time graph. Velocity Velocity usually describes speed. However, it describes both the rate of motion and the direction of an object. Scalar quantity A scalar quantity measures how much. (ex. distance) Vector Quantity A vector quantity measures how much and in what direction. (ex. 20m/s North) _ v What type of quantity? Vector quantities have an arrow above the symbol. Distance travelled (Type of quantity and description) Distance travelled is a scalar quantity that measures the change in distance of an object moving from a starting point. Displacement (Type of quantity and description) Displacement is a vector quantity that describes the the measurement of the change in distance and the direction or change of position in an object. v What type of quantity? A scalar quantity is written without an arrow above it. The X-axis method This is a way of determining vector directions using the mathematical method of setting up a coordinate grid (with an x axis and a y axis.) Directions are stated from the x axis, which is the starting reference point at 0 degrees. From there directions are determined in a counter clockwise direction. Positive and Negative Directions (X axis method) Directions given along the x and y axis lines are given positive or negative values. -UP and RIGHT are POSITIVE -DOWN and LEFT are NEGATIVE -Directions in BETWEEN the axis lines are NOT given a positive or negative value. The navigator method The navigator method uses the directions of North (N), South (S), East (E) an West (W). North is the starting reference point of 0 degrees. Directions are stated CLOCKWISE from the north. (N) and (E) are positive (S) and (W) are negative Average Velocity Average velocity is uniform motion that involves changing a position in a specified time. (ex. 2m/s [E] ) Acceleration Acceleration is the change in velocity during a specific time interval. It is a vector quantity. Different types of acceleration are possible because the magnitude and direction of the velocity can change. Positive Acceleration Positive Acceleration occurs in to ways. 1) When the change in both the magnitude of the velocity and the direction are positive. 2) When the change in both the magnitude and the direction are negative. Negative Acceleration Negative Acceleration occurs in two ways. 1) When the change in the magnitude of the velocity is negative while the direction is positive. 2) When the change in the magnitude of the velocity is positive while the direction is negative. Force Force is defined as a push or pull on an object. It is measured in newtons. With an unbalanced force, the force acting in one direction is greater than the force acting in the opposite direction. *An unbalanced force will usually result in a change of speed (acceleration). Work Whenever a force moves an object through a distance that is in the direction of the force, then work is being done on the object. Conditions of Work 1) There must be movement 2) There must be a force 3) The force and the distance travelled must be in the same direction. Work input/output When a force is applied to move an object through a distance, work is one on the object. This called work input or energy input. The object gains energy as a result. This is called energy output or work output. The absence of outside forces, like friction, means that the work input should b equal to the work output. Work VS Energy Energy is the ability to do work. Work and energy are actually the same thing. (Ex. If a body does work on an object, then the body loses energy.) 1st Rule- Law of Inertia 1st Rule- Law of Inertia states an object moving uniformly in a straight line (or sitting still) will keep doing that until an unbalanced force acts on it. This unbalanced force will result in an acceleration of this object. 3rd Rule/Law 3rd Law For every force, there is an equal force in the opposite direction 2nd Law 2nd Law Acceleration of an object will vary directly with the applied unbalanced force and inversely with the object's mass. Force Formula kg X m Newtons = ________ s^2 Work Formula Work=F X d joule= newton X metre Acceleration Formula change in velocity Acceleration = ------------------------------ time interval Average Velocity Formula displacement Average Velocity = -------------------------- time elapsed Displacement Formula Displacement = d final- d initial where d = displacement

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